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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH -next RFC v3 0/8] improve tag allocation under heavy load Content-Language: en-US To: "yukuai (C)" , axboe@kernel.dk, bvanassche@acm.org, andriy.shevchenko@linux.intel.com, john.garry@huawei.com, ming.lei@redhat.com, qiulaibin@huawei.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com References: <20220415101053.554495-1-yukuai3@huawei.com> <3fbadd9f-11dd-9043-11cf-f0839dcf30e1@opensource.wdc.com> <63e84f2a-2487-a0c3-cab2-7d2011bc2db4@huawei.com> <55e8b04f-0d2f-2ce1-6514-5abd0b67fd48@opensource.wdc.com> <6957af40-8720-d74b-5be7-6bcdd9aa1089@huawei.com> <237a43f0-3b09-46d0-e73c-57ef51e39590@opensource.wdc.com> <2e7969ea-68d0-964a-808e-ee8943de70e3@opensource.wdc.com> <35f18afa-0db1-b423-5824-4d5631b0422f@huawei.com> From: Damien Le Moal Organization: Western Digital Research In-Reply-To: <35f18afa-0db1-b423-5824-4d5631b0422f@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/25/22 16:28, yukuai (C) wrote: > =E5=9C=A8 2022/04/25 15:06, Damien Le Moal =E5=86=99=E9=81=93: >=20 >>>> By the way, did you check that doing something like: >>>> >>>> echo 2048 > /sys/block/sdX/queue/nr_requests >>>> >>>> improves performance for your high number of jobs test case ? >>> >>> Yes, performance will not degrade when numjobs is not greater than 25= 6 >>> in this case. >> >> That is my thinking as well. I am asking if did check that (did you ru= n it ?). >=20 > Hi, >=20 > I'm sure I ran it with 256 jobs before. >=20 > However, I didn't run it with 512 jobs. And following is the result I > just tested: What was nr_requests ? The default 64 ? If you increase that number, do you see better throughput/more requests being sequential ? >=20 > ratio of sequential io: 49.1% >=20 > Read|Write seek=20 >=20 > cnt 99338, zero cnt 48753=20 >=20 > >=3D(KB) .. <(KB) : count ratio |distribution=20 > | > 0 .. 1 : 48753 49.1%=20 > |########################################| > 1 .. 2 : 0 0.0% |=20 > | > 2 .. 4 : 0 0.0% |=20 > | > 4 .. 8 : 0 0.0% |=20 > | > 8 .. 16 : 0 0.0% |=20 > | > 16 .. 32 : 0 0.0% |=20 > | > 32 .. 64 : 0 0.0% |=20 > | > 64 .. 128 : 4975 5.0% |#####=20 > | > 128 .. 256 : 4439 4.5% |####=20 > | > 256 .. 512 : 2615 2.6% |###=20 > | > 512 .. 1024 : 967 1.0% |#=20 > | > 1024 .. 2048 : 213 0.2% |#=20 > | > 2048 .. 4096 : 375 0.4% |#=20 > | > 4096 .. 8192 : 723 0.7% |#=20 > | > 8192 .. 16384 : 1436 1.4% |##=20 > | > 16384 .. 32768 : 2626 2.6% |###=20 > | > 32768 .. 65536 : 4197 4.2% |####=20 > | > 65536 .. 131072 : 6431 6.5% |######=20 > | > 131072 .. 262144 : 7590 7.6% |#######=20 > | > 262144 .. 524288 : 6433 6.5% |######=20 > | > 524288 .. 1048576 : 4583 4.6% |####=20 > | > 1048576 .. 2097152 : 2237 2.3% |##=20 > | > 2097152 .. 4194304 : 489 0.5% |#=20 > | > 4194304 .. 8388608 : 83 0.1% |#=20 > | > 8388608 .. 16777216 : 36 0.0% |#=20 > | > 16777216 .. 33554432 : 0 0.0% |=20 > | > 33554432 .. 67108864 : 0 0.0% |=20 > | > 67108864 .. 134217728 : 137 0.1% |#=20 > | --=20 Damien Le Moal Western Digital Research